First of all, sorry but I'm a complete newbie with this phone, however I've tried to do the necessary research and I think i've hit a block. First of all, my phone is a SGH-1747 (from the title) Samsung Galaxy s III 4G LTE or just Samsung Galaxy s III LTE which is network unlocked with original carrier being AT&T. I updated the phone to Jelly Bean 4.1.1 via Samsung Kies and everything went smoothly. It was originally my aunt's and I asked her to ship it to me here in Australia. So my current provider is Vodafone Australia and yes I do have a micro sim and can use the phone for almost everything except for the problem that I'm experiencing.
Okay so firstly I thought my problem was that everything I go on google play store via my mobile data (not WIFI), I was unable to update / download certain apps and it would give me a "package file is invalid" error. I've done researched tried clearing cache, cookies, data but nothing seemed to work. I also thought it might be something to do with only unable to download apps that are a certain size, seeing as I could download SOME smaller apps (like google apps updates, but not all) but it got to the point where I tried accessing apps that require an internet connection, and it won't load because of error "not connected to internet or you might be disconnected". At all times I am able to access the internet via internet browser and even search for apps via google play store. I also thought it might be app-related, so i tried different apps, no bingo. I can however download all these apps / updates when I am connected to WIFI at my house, can even access the games. Also thought it might be related to Vodafone not supporting 4G so I tried to change around the network modes but It didn't really make much of a difference... I've also tried factory resetting many times with no bingo.
So now i'm at the point where I don't know what's wrong with it. Do you guys have any ideas? Even vodafone people were unable to find a solution after spending about an hour trying to fix it with them.